In general, an LCD apparatus displays image information using electro-optics properties of a liquid crystal. Some LCD apparatus transmits a light when an electric field is not applied to the liquid crystal. But some LCD apparatus intercepts a light when an electric field is not applied to the liquid crystal, and transmits the light when the electric field is applied to the liquid crystal.
Some LCD apparatus intercepts a light when an electric field is not applied to the liquid crystal, and the LCD apparatus transmits the light when the electric field is applied to the liquid crystal.
In order to precisely transmit the light through the liquid crystal, the light that is able to transmit the liquid crystal should be supplied to the liquid crystal after uniformly aligning the liquid crystal toward an uniform direction. An alignment of the liquid crystal is performed by means of an alignment film, and the light that is able to transmit the liquid crystal can be obtained by a polarizing plate.
The alignment film is as a polyimide thin film layer. When rubbing the alignment film against a rubbing cloth toward the uniform direction, an alignment groove is formed on the alignment film. The alignment of the liquid crystal is performed by means of the alignment groove. The rubbing cloth wind around an outer circumference of a rubbing roller, and the alignment groove is formed on the alignment film by rubbing the rubbing roller having the rubbing cloth against the alignment film.
Hereinafter, manufacturing processes of the rubbing cloth will be described with reference to FIGS. 1A to 1F. Here, a term referred to as a “rubbing cloth fabric” indicates a cloth having a length and a width shorter than the length.
Referring to FIG. 1A, the rubbing cloth fabric 100 is manufactured by interweaving a weft 1 with a warp 2, the warp 2 intersecting the weft 1 and having a length longer than that of the weft 1. The rubbing cloth fabric 100 includes a rubbing pile 110 irregularly formed on the rubbing cloth fabric 100 as shown in FIGS. 1B and 1C.
FIG. 1D is a view showing a process for aligning the rubbing pile irregularly formed on the rubbing cloth fabric.
Referring to FIG. 1D, a roller brush 200 for rearranging the rubbing pile 110 is disposed in a direction parallel to a width direction of the rubbing cloth fabric 100. The width direction is the same direction in which the weft 1 is formed on the rubbing cloth fabric 100. When the roller brush 200, which is in contact with the rubbing cloth fabric 100, is transferred, the rubbing pile 110 is realigned in a direction parallel to the warp 2. The realigned rubbing pile has been allowed to have a reference numeral “115”.
As shown in FIG. 1E, the rubbing cloth fabric 100 having the realigned rubbing pile 115 is cut into pieces. A piece of rubbing cloth fabric which is cut from the rubbing cloth fabric 100 is defined as a rubbing cloth 150.
The rubbing cloth 150 is attached onto a rubbing roller 300 which has a length longer than a width of the alignment film. In order to attach the rubbing cloth 150 onto the rubbing roller 300, the rubbing cloth 150 has a length similar to a length of the rubbing roller 300, and has a width similar to a length of the circumference surface of the rubbing roller 300. That is, the warp 2 of the rubbing cloth 150 is aligned along the circumference surface of the rubbing roller 300, the weft 1 is aligned in the length direction of the rubbing roller 300, and the rubbing pile 110 is aligned parallel to the weft 1.
As shown in FIG. 1F, when the rubbing roller 300, on which the rubbing cloth 150 is wound, rotates and simultaneously applies pressure to the alignment film 400, the alignment groove is formed on the alignment film 400.
However, when the alignment groove is formed by means of the conventional rubbing roller 300 to which the rubbing cloth 150 is attached, the liquid crystal cannot be precisely aligned with the alignment groove due to a scratch formed on the alignment film 400. It is difficult to totally control a tension of the rubbing cloth fabric 100 when the rubbing roller 300 is rubbed against the alignment film 400 along the warp 2. When the tension of the rubbing cloth fabric 100 is not precisely controlled, the rubbing pile 110 is irregularly distributed on the rubbing cloth fabric 100. Therefore, the liquid crystal cannot be precisely aligned with the alignment groove.
Also, when the alignment film 500 has a larger size than that of the rubbing cloth 150, as shown as reference numeral 500 in FIG. 1E, it is not possible to form the alignment groove by means of the rubbing cloth fabric 100 having a width shorter than that of the alignment film 500.